You receive a "Limited or no connectivity" message on a computer that is connected to the Internet by a DSL modem or by a cable modem after you install Windows XP Service Pack 2

After you install Windows XP Service Pack 2 on a computer that is connected to the Internet by a DSL modem or by a cable modem, you may receive anerror message that resembles the following:

This error message can be caused by several things. This article discusses the most likely causes and suggests what you can try to resolve the issue. However, this error message can also be displayed when, in fact, you are already connected to the Internet. If that is the case, you can safely ignore the error message.

First try to determine whether you can connect to the Internet

You should first try to determine whether you can connect to the Internet. If you can connect, the error message is obviously incorrect. If that is the case, you might want to disable the error message. To disable the error message, follow these steps.

1. Click Start, and then click Run.
2. In the Open box, type ncpa.cpl, and then press ENTER. The Network Connections dialog box opens.
3. Double-click Local Area Connection, and then click Properties.
4. On the General tab, click to clear the Notify me when this connection has limited or no connectivity check box.
5. Click OK, and then click Close.

Check for other causes and solutions

If you cannot connect to the Internet, you have to find the reason. Realize that the reason may not be with your computer, but may be an issue with your Internet service provider (ISP) or with issues on the network at your work. Therefore, for some of these solutions, you might need help from your ISP, or, if your computer is part of a network at work, you may have to ask your network administrator for help.

Contact your ISP service

If you use an ISP to connect to the Internet, before you go any further, first contact your ISP to see whether it is experiencing any problems. If the ISP has problems, wait until the problems are resolved before you continue to troubleshoot.

Check the hardware devices

If you still cannot connect to the Internet after you have confirmation that your ISP is not experiencing any problems, manually check the hardware devices on your small office network or your home network for problems. For example, if a hub, router, modem, or access point is installed on your network, check that it is connected correctly, and that it is turned on and functioning properly. The solution might be as simple as turning on or restarting a hardware device, and then restarting your computer. For more specific troubleshooting information about the hardware devices that you are using, refer to the hardware documentation for your devices.

Run the Network Diagnotics tool

If checking and restarting your hardware device did not resolve the issue, your computer may have a networking problem. For example, your computer may not have an IP address or your TCP/IP settings may be corrupted.

There are tools available in Windows XP that you can use to help you diagnose and troubleshoot networking problems. To use the Network Diagnostics tool to determine the source of the issue, follow these steps:

1. Click Start, and then click Help and Support.
2. Under Pick a task, click the link to Use Tools to view your computer information and diagnose problems, and then click Network Diagnostics in the list on the left.
3. Click Scan your system. The Network Diagnostics tool collects configuration information and performs automated troubleshooting of the network connection.
4. When the process is complete, look for any items that are marked "FAILED" in red.
   
   Note If you do not see any categories that failed, please see the "Additional troubleshooting information" section for more information about how to troubleshoot network problems.
5. Expand a category to view the testing results. For example, to check the results for TCP/IP settings, expand the Network Adapters section. Then, check whether a network adapter has failed.
6. You can use that information to try to resolve the issue yourself, or you can provide the information to your network administrator for help. If you are not sure how to use the results from the Network Diagnostics tool to resolve the issue, see the "Next steps" section for help.

Additional troubleshooting information for TCP/IP issues

For more information about how to troubleshoot TCP/IP networking problems and use the Network Diagnostics tool, click the following article number to view the article in the Microsoft Knowledge Base: For more information about how to troubleshoot home networking in Windows XP, click the following article number to view the article in the Microsoft Knowledge Base: If the Network Diagnostics tool did not help you resolve the issue, try the next solution "Check the hardware device" in this article for help.

Check the network adapter on your computer

If you did not find a resolution by using the Network Diagnostics tool, check the network adapter on your computer to make sure that it is enabled. If it is enabled, you can sometimes solve connection problems by disabling and then re-enabling the adapter. If you are not sure how to check the network adapter, check the help that is provided with the network adapter.

Check your Dynamic Host Configuration Protocol (DHCP) server

If the network adapter is working correctly, the next thing to check is whether your DHCP server is down or is not available on the network.

To troubleshoot issues with the DHCP server, it is important to know where the DHCP server is located. If you are not sure, it is probably hosted by your ISP (if you use an ISP), on another computer (if you are on a work network), or on a router (on your small office network or home network). Use the following suggestions, depending on the network setup:

• If you use an ISP
  
  If you have not already done this, contact the ISP to see whether they are experiencing any problems. If they are, wait until their problems are resolved. If the ISP is not experiencing any problems, this is probably not the problem that is causing the issue.
• If you are on a work network
  
  On a work network, the network administrator probably maintains the DHCP server and should be able to tell you if the server is down or has problems. Let them know that you have problems with your Internet connection, and see whether they can help you. If you do not have a network administrator or other support person to contact for help, you can use the Microsoft Customer Support Services Web site to find other solutions to your problem. See the "Next steps" section for more information.
• If you have a router on your small office network or home network
  
  If you have a router on your small office network or home network, then the DHCP server might be hosted on the router. If you have not already done this, check that the router is working correctly. For example, you can check whether the router is turned on and that the wires are connected correctly. You might have to check the router documentation for troubleshooting help if you are not sure what to do, or contact the person who set up the network for help.

Check your Wired Equivalent Privacy (WEP) key

If your computer uses a wireless network, you may be required to supply a WEP key. (A WEP key is a network security key that is used to help protect your wireless network.) If you supply an incorrect key, or if you do not have a WEP key set, you will be unable to connect to the network. Therefore, make sure that you have the correct WEP key if it is required. For more information, see the help provided with your wireless network device or ask the person who set up the wireless network for help.

If these troubleshooting steps did not help, see the "Next Steps" section for other sources that may help you resolve your problem.

If these methods did not resolved your issue, you may want to ask someone you know for help, or you may want to contact your ISP service or network administrator for help. You can also use the Microsoft Customer Support Services Web site to find other solutions to your problem. Some services that the Microsoft Customer Support Services Web site provides include the following:

• Searchable Knowledge Base (http://support.microsoft.com/search/?adv=1) : Search technical support information and self-help tools for Microsoft products.
• Solution Centers (http://support.microsoft.com/select/?target=hub) : View product-specific frequently asked questions and support highlights.
• Microsoft Product Support Newsgroups (http://www.microsoft.com/communities/newsgroups/default.mspx) : Contact counterparts, peers, and Microsoft Most Valuable Professionals (MVPs).
• Other Support Options (http://support.microsoft.com/default.aspx?pr=csshome) : Use the Web to ask a question, contact Microsoft Customer Support Services, or provide feedback.

If you continue to have problems after you use these Microsoft Web sites or if you cannot find a solution to the problem on the Microsoft Support Services Web site, click the following link to contact Support.

For more information about how to troubleshoot Internet connectivity in Windows XP, click the following article number to view the article in the Microsoft Knowledge Base: You may also find the following Web site helpful when you troubleshoot network connectivity problems: